Which of the Choices Below BEST Depicts the Flow of Carbon

Which of the choices below BEST depicts the flow of carbon between primary producers, consumers, and decomposers?

A) primary producers $\rightarrow$ consumers $\rightarrow$ decomposers
B) consumers $\rightarrow$ primary producers $\rightarrow$ decomposers
C) decomposers $\rightarrow$ consumers $\rightarrow$ primary producers